The Gubong Project consists of a number of historical underground mines within ca. 20km of each other, including the Gubong Mine area itself, which is host to numerous historical mines that have exploited multiple gold-bearing orogenic quartz veins over 5km along strike and several kilometres across strike.
Gubong was South Korea’s largest gold producer from 1930-1943, during the Japanese occupation, and still retains a substantial remnant reef between mined blocks and excellent exploration potential. Mine data indicates good potential for mine re-commissioning and the possibility of relatively early cash flow.
The immediate Gubong project area hosts five historical underground mines with the largest being the Gubong mine which exploited high grade quartz veins (Vein 6 being the main lode) hosted in gneissic granite and mined to a vertical depth of approximately 1500m.
Historic underground sampling results of the deeper levels of Vein 6 gives an arithmetic uncut average of 30.6 g/t gold from 146 values. Exploratory core drilling below the now abandoned mine workings from one of five holes returned 27.9 g/t gold and 25 g/t silver over 1.6 metres downhole from 845.2 metres. This demonstration of the persistence with depth of the most developed mineralised structure supports the prospectivity of the property for auriferous shoots with considerable depth continuity.
Interestingly Vein No 6, the main vein exploited at Gubong, was found as a blind vein in the hanging wall during mine development work on the other veins. This suggests substantial gold resources may be found in parallel vein systems that do not outcrop in the area. This has important implications for exploration methods when following up historically mined areas – veins may have been missed by previous workers and more modern exploration techniques may help to uncover them.
In addition to the Gubong Mine, the Gubong District hosts a number of brownfields exploration opportunities that, if resources were proven up, would be within trucking distance of a potential Gubong Mine central milling facility.
Proof of concept drilling at Gubong in 2015 hit relatively shallow orogenic quartz veining in most drill holes near to the modelled veins/structures, including a higher grade intercept of 0.4m @ 5.18g/t Au at Danbong (a ca. 1km strike length of vein with no previous production/mining, thus preserving near-surface potential). The ability to engage local drilling contractors, secure land access (including on farms), model the historical data as available, and hit veining, including mineralisation, shows that the drilling program was a success. Furthermore, surface rock chip samples taken in 2015 confirm high grade veining exists (peak result of 25.4g/t Au).
Foreign Estimates of Resources: Gubong District
Exploration Target Range
Gubong has an exploration target range (see Appendix 3 for details) already established for Vein 6 extension through work undertaken by Asiatic, as follows:
- Lower Range Exploration Target - 1.21 million tonnes at 6 g/t gold (230,000oz Au);
- Upper Range Exploration Target - 2.28 million tonnes at 8 g/t gold (580,000oz Au).
The exploration carried out to-date is insufficient to estimate a resource and it is uncertain whether further exploration will result in the estimation of a resource.
This project has the potential to be advanced relatively quickly with the right backing on underground mine execution to allow access to historically worked drives and crosscuts. The district has also not seen systematic modern exploration and several quartz veins remain to be defined: e.g. the Guryeong and Bongam veins.